DMA: OF: Check properties value before running be32_to_cpup() on it

In of_dma_controller_register() routine we are calling of_get_property() as an
parameter to be32_to_cpup(). In case the property doesn't exist we will get a
crash.

This patch changes this code to check if we got a valid property first and then
runs be32_to_cpup() on it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index 6036cd08e222..00db454f70d3 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -93,6 +93,7 @@ int of_dma_controller_register(struct device_node *np,
 {
         struct of_dma   *ofdma;
         int             nbcells;
+        const __be32    *prop;
 
         if (!np || !of_dma_xlate) {
                 pr_err("%s: not enough information provided\n", __func__);
@@ -103,8 +104,11 @@ int of_dma_controller_register(struct device_node *np,
         if (!ofdma)
                 return -ENOMEM;
 
-        nbcells = be32_to_cpup(of_get_property(np, "#dma-cells", NULL));
-        if (!nbcells) {
+        prop = of_get_property(np, "#dma-cells", NULL);
+        if (prop)
+                nbcells = be32_to_cpup(prop);
+
+        if (!prop || !nbcells) {
                 pr_err("%s: #dma-cells property is missing or invalid\n",
                        __func__);
                 kfree(ofdma);